blob: cce022435dbc95ff562b28cd073b2d239206af52 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 */
17
18#include <linux/config.h>
19#include <linux/slab.h>
20#include <linux/mm.h>
21#include <linux/hugetlb.h>
22#include <linux/shm.h>
23#include <linux/init.h>
24#include <linux/file.h>
25#include <linux/mman.h>
26#include <linux/proc_fs.h>
27#include <linux/shmem_fs.h>
28#include <linux/security.h>
29#include <linux/syscalls.h>
30#include <linux/audit.h>
Stephen Rothwell7d87e142005-05-01 08:59:12 -070031#include <linux/ptrace.h>
32
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <asm/uaccess.h>
34
35#include "util.h"
36
37#define shm_flags shm_perm.mode
38
39static struct file_operations shm_file_operations;
40static struct vm_operations_struct shm_vm_ops;
41
42static struct ipc_ids shm_ids;
43
44#define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
45#define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
46#define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
47#define shm_buildid(id, seq) \
48 ipc_buildid(&shm_ids, id, seq)
49
50static int newseg (key_t key, int shmflg, size_t size);
51static void shm_open (struct vm_area_struct *shmd);
52static void shm_close (struct vm_area_struct *shmd);
53#ifdef CONFIG_PROC_FS
54static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
55#endif
56
57size_t shm_ctlmax = SHMMAX;
58size_t shm_ctlall = SHMALL;
59int shm_ctlmni = SHMMNI;
60
61static int shm_tot; /* total number of shared memory pages */
62
63void __init shm_init (void)
64{
65 ipc_init_ids(&shm_ids, 1);
66#ifdef CONFIG_PROC_FS
67 create_proc_read_entry("sysvipc/shm", 0, NULL, sysvipc_shm_read_proc, NULL);
68#endif
69}
70
71static inline int shm_checkid(struct shmid_kernel *s, int id)
72{
73 if (ipc_checkid(&shm_ids,&s->shm_perm,id))
74 return -EIDRM;
75 return 0;
76}
77
78static inline struct shmid_kernel *shm_rmid(int id)
79{
80 return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
81}
82
83static inline int shm_addid(struct shmid_kernel *shp)
84{
85 return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
86}
87
88
89
90static inline void shm_inc (int id) {
91 struct shmid_kernel *shp;
92
93 if(!(shp = shm_lock(id)))
94 BUG();
95 shp->shm_atim = get_seconds();
96 shp->shm_lprid = current->tgid;
97 shp->shm_nattch++;
98 shm_unlock(shp);
99}
100
101/* This is called by fork, once for every shm attach. */
102static void shm_open (struct vm_area_struct *shmd)
103{
104 shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
105}
106
107/*
108 * shm_destroy - free the struct shmid_kernel
109 *
110 * @shp: struct to free
111 *
112 * It has to be called with shp and shm_ids.sem locked,
113 * but returns with shp unlocked and freed.
114 */
115static void shm_destroy (struct shmid_kernel *shp)
116{
117 shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
118 shm_rmid (shp->id);
119 shm_unlock(shp);
120 if (!is_file_hugepages(shp->shm_file))
121 shmem_lock(shp->shm_file, 0, shp->mlock_user);
122 else
123 user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
124 shp->mlock_user);
125 fput (shp->shm_file);
126 security_shm_free(shp);
127 ipc_rcu_putref(shp);
128}
129
130/*
131 * remove the attach descriptor shmd.
132 * free memory for segment if it is marked destroyed.
133 * The descriptor has already been removed from the current->mm->mmap list
134 * and will later be kfree()d.
135 */
136static void shm_close (struct vm_area_struct *shmd)
137{
138 struct file * file = shmd->vm_file;
139 int id = file->f_dentry->d_inode->i_ino;
140 struct shmid_kernel *shp;
141
142 down (&shm_ids.sem);
143 /* remove from the list of attaches of the shm segment */
144 if(!(shp = shm_lock(id)))
145 BUG();
146 shp->shm_lprid = current->tgid;
147 shp->shm_dtim = get_seconds();
148 shp->shm_nattch--;
149 if(shp->shm_nattch == 0 &&
150 shp->shm_flags & SHM_DEST)
151 shm_destroy (shp);
152 else
153 shm_unlock(shp);
154 up (&shm_ids.sem);
155}
156
157static int shm_mmap(struct file * file, struct vm_area_struct * vma)
158{
159 file_accessed(file);
160 vma->vm_ops = &shm_vm_ops;
161 shm_inc(file->f_dentry->d_inode->i_ino);
162 return 0;
163}
164
165static struct file_operations shm_file_operations = {
166 .mmap = shm_mmap
167};
168
169static struct vm_operations_struct shm_vm_ops = {
170 .open = shm_open, /* callback for a new vm-area open */
171 .close = shm_close, /* callback for when the vm-area is released */
172 .nopage = shmem_nopage,
173#ifdef CONFIG_NUMA
174 .set_policy = shmem_set_policy,
175 .get_policy = shmem_get_policy,
176#endif
177};
178
179static int newseg (key_t key, int shmflg, size_t size)
180{
181 int error;
182 struct shmid_kernel *shp;
183 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
184 struct file * file;
185 char name[13];
186 int id;
187
188 if (size < SHMMIN || size > shm_ctlmax)
189 return -EINVAL;
190
191 if (shm_tot + numpages >= shm_ctlall)
192 return -ENOSPC;
193
194 shp = ipc_rcu_alloc(sizeof(*shp));
195 if (!shp)
196 return -ENOMEM;
197
198 shp->shm_perm.key = key;
199 shp->shm_flags = (shmflg & S_IRWXUGO);
200 shp->mlock_user = NULL;
201
202 shp->shm_perm.security = NULL;
203 error = security_shm_alloc(shp);
204 if (error) {
205 ipc_rcu_putref(shp);
206 return error;
207 }
208
209 if (shmflg & SHM_HUGETLB) {
210 /* hugetlb_zero_setup takes care of mlock user accounting */
211 file = hugetlb_zero_setup(size);
212 shp->mlock_user = current->user;
213 } else {
214 sprintf (name, "SYSV%08x", key);
215 file = shmem_file_setup(name, size, VM_ACCOUNT);
216 }
217 error = PTR_ERR(file);
218 if (IS_ERR(file))
219 goto no_file;
220
221 error = -ENOSPC;
222 id = shm_addid(shp);
223 if(id == -1)
224 goto no_id;
225
226 shp->shm_cprid = current->tgid;
227 shp->shm_lprid = 0;
228 shp->shm_atim = shp->shm_dtim = 0;
229 shp->shm_ctim = get_seconds();
230 shp->shm_segsz = size;
231 shp->shm_nattch = 0;
232 shp->id = shm_buildid(id,shp->shm_perm.seq);
233 shp->shm_file = file;
234 file->f_dentry->d_inode->i_ino = shp->id;
235 if (shmflg & SHM_HUGETLB)
236 set_file_hugepages(file);
237 else
238 file->f_op = &shm_file_operations;
239 shm_tot += numpages;
240 shm_unlock(shp);
241 return shp->id;
242
243no_id:
244 fput(file);
245no_file:
246 security_shm_free(shp);
247 ipc_rcu_putref(shp);
248 return error;
249}
250
251asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
252{
253 struct shmid_kernel *shp;
254 int err, id = 0;
255
256 down(&shm_ids.sem);
257 if (key == IPC_PRIVATE) {
258 err = newseg(key, shmflg, size);
259 } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
260 if (!(shmflg & IPC_CREAT))
261 err = -ENOENT;
262 else
263 err = newseg(key, shmflg, size);
264 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
265 err = -EEXIST;
266 } else {
267 shp = shm_lock(id);
268 if(shp==NULL)
269 BUG();
270 if (shp->shm_segsz < size)
271 err = -EINVAL;
272 else if (ipcperms(&shp->shm_perm, shmflg))
273 err = -EACCES;
274 else {
275 int shmid = shm_buildid(id, shp->shm_perm.seq);
276 err = security_shm_associate(shp, shmflg);
277 if (!err)
278 err = shmid;
279 }
280 shm_unlock(shp);
281 }
282 up(&shm_ids.sem);
283
284 return err;
285}
286
287static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
288{
289 switch(version) {
290 case IPC_64:
291 return copy_to_user(buf, in, sizeof(*in));
292 case IPC_OLD:
293 {
294 struct shmid_ds out;
295
296 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
297 out.shm_segsz = in->shm_segsz;
298 out.shm_atime = in->shm_atime;
299 out.shm_dtime = in->shm_dtime;
300 out.shm_ctime = in->shm_ctime;
301 out.shm_cpid = in->shm_cpid;
302 out.shm_lpid = in->shm_lpid;
303 out.shm_nattch = in->shm_nattch;
304
305 return copy_to_user(buf, &out, sizeof(out));
306 }
307 default:
308 return -EINVAL;
309 }
310}
311
312struct shm_setbuf {
313 uid_t uid;
314 gid_t gid;
315 mode_t mode;
316};
317
318static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
319{
320 switch(version) {
321 case IPC_64:
322 {
323 struct shmid64_ds tbuf;
324
325 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
326 return -EFAULT;
327
328 out->uid = tbuf.shm_perm.uid;
329 out->gid = tbuf.shm_perm.gid;
330 out->mode = tbuf.shm_flags;
331
332 return 0;
333 }
334 case IPC_OLD:
335 {
336 struct shmid_ds tbuf_old;
337
338 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
339 return -EFAULT;
340
341 out->uid = tbuf_old.shm_perm.uid;
342 out->gid = tbuf_old.shm_perm.gid;
343 out->mode = tbuf_old.shm_flags;
344
345 return 0;
346 }
347 default:
348 return -EINVAL;
349 }
350}
351
352static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
353{
354 switch(version) {
355 case IPC_64:
356 return copy_to_user(buf, in, sizeof(*in));
357 case IPC_OLD:
358 {
359 struct shminfo out;
360
361 if(in->shmmax > INT_MAX)
362 out.shmmax = INT_MAX;
363 else
364 out.shmmax = (int)in->shmmax;
365
366 out.shmmin = in->shmmin;
367 out.shmmni = in->shmmni;
368 out.shmseg = in->shmseg;
369 out.shmall = in->shmall;
370
371 return copy_to_user(buf, &out, sizeof(out));
372 }
373 default:
374 return -EINVAL;
375 }
376}
377
378static void shm_get_stat(unsigned long *rss, unsigned long *swp)
379{
380 int i;
381
382 *rss = 0;
383 *swp = 0;
384
385 for (i = 0; i <= shm_ids.max_id; i++) {
386 struct shmid_kernel *shp;
387 struct inode *inode;
388
389 shp = shm_get(i);
390 if(!shp)
391 continue;
392
393 inode = shp->shm_file->f_dentry->d_inode;
394
395 if (is_file_hugepages(shp->shm_file)) {
396 struct address_space *mapping = inode->i_mapping;
397 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
398 } else {
399 struct shmem_inode_info *info = SHMEM_I(inode);
400 spin_lock(&info->lock);
401 *rss += inode->i_mapping->nrpages;
402 *swp += info->swapped;
403 spin_unlock(&info->lock);
404 }
405 }
406}
407
408asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
409{
410 struct shm_setbuf setbuf;
411 struct shmid_kernel *shp;
412 int err, version;
413
414 if (cmd < 0 || shmid < 0) {
415 err = -EINVAL;
416 goto out;
417 }
418
419 version = ipc_parse_version(&cmd);
420
421 switch (cmd) { /* replace with proc interface ? */
422 case IPC_INFO:
423 {
424 struct shminfo64 shminfo;
425
426 err = security_shm_shmctl(NULL, cmd);
427 if (err)
428 return err;
429
430 memset(&shminfo,0,sizeof(shminfo));
431 shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
432 shminfo.shmmax = shm_ctlmax;
433 shminfo.shmall = shm_ctlall;
434
435 shminfo.shmmin = SHMMIN;
436 if(copy_shminfo_to_user (buf, &shminfo, version))
437 return -EFAULT;
438 /* reading a integer is always atomic */
439 err= shm_ids.max_id;
440 if(err<0)
441 err = 0;
442 goto out;
443 }
444 case SHM_INFO:
445 {
446 struct shm_info shm_info;
447
448 err = security_shm_shmctl(NULL, cmd);
449 if (err)
450 return err;
451
452 memset(&shm_info,0,sizeof(shm_info));
453 down(&shm_ids.sem);
454 shm_info.used_ids = shm_ids.in_use;
455 shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
456 shm_info.shm_tot = shm_tot;
457 shm_info.swap_attempts = 0;
458 shm_info.swap_successes = 0;
459 err = shm_ids.max_id;
460 up(&shm_ids.sem);
461 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
462 err = -EFAULT;
463 goto out;
464 }
465
466 err = err < 0 ? 0 : err;
467 goto out;
468 }
469 case SHM_STAT:
470 case IPC_STAT:
471 {
472 struct shmid64_ds tbuf;
473 int result;
474 memset(&tbuf, 0, sizeof(tbuf));
475 shp = shm_lock(shmid);
476 if(shp==NULL) {
477 err = -EINVAL;
478 goto out;
479 } else if(cmd==SHM_STAT) {
480 err = -EINVAL;
481 if (shmid > shm_ids.max_id)
482 goto out_unlock;
483 result = shm_buildid(shmid, shp->shm_perm.seq);
484 } else {
485 err = shm_checkid(shp,shmid);
486 if(err)
487 goto out_unlock;
488 result = 0;
489 }
490 err=-EACCES;
491 if (ipcperms (&shp->shm_perm, S_IRUGO))
492 goto out_unlock;
493 err = security_shm_shmctl(shp, cmd);
494 if (err)
495 goto out_unlock;
496 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
497 tbuf.shm_segsz = shp->shm_segsz;
498 tbuf.shm_atime = shp->shm_atim;
499 tbuf.shm_dtime = shp->shm_dtim;
500 tbuf.shm_ctime = shp->shm_ctim;
501 tbuf.shm_cpid = shp->shm_cprid;
502 tbuf.shm_lpid = shp->shm_lprid;
503 if (!is_file_hugepages(shp->shm_file))
504 tbuf.shm_nattch = shp->shm_nattch;
505 else
506 tbuf.shm_nattch = file_count(shp->shm_file) - 1;
507 shm_unlock(shp);
508 if(copy_shmid_to_user (buf, &tbuf, version))
509 err = -EFAULT;
510 else
511 err = result;
512 goto out;
513 }
514 case SHM_LOCK:
515 case SHM_UNLOCK:
516 {
517 shp = shm_lock(shmid);
518 if(shp==NULL) {
519 err = -EINVAL;
520 goto out;
521 }
522 err = shm_checkid(shp,shmid);
523 if(err)
524 goto out_unlock;
525
526 if (!capable(CAP_IPC_LOCK)) {
527 err = -EPERM;
528 if (current->euid != shp->shm_perm.uid &&
529 current->euid != shp->shm_perm.cuid)
530 goto out_unlock;
531 if (cmd == SHM_LOCK &&
532 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
533 goto out_unlock;
534 }
535
536 err = security_shm_shmctl(shp, cmd);
537 if (err)
538 goto out_unlock;
539
540 if(cmd==SHM_LOCK) {
541 struct user_struct * user = current->user;
542 if (!is_file_hugepages(shp->shm_file)) {
543 err = shmem_lock(shp->shm_file, 1, user);
544 if (!err) {
545 shp->shm_flags |= SHM_LOCKED;
546 shp->mlock_user = user;
547 }
548 }
549 } else if (!is_file_hugepages(shp->shm_file)) {
550 shmem_lock(shp->shm_file, 0, shp->mlock_user);
551 shp->shm_flags &= ~SHM_LOCKED;
552 shp->mlock_user = NULL;
553 }
554 shm_unlock(shp);
555 goto out;
556 }
557 case IPC_RMID:
558 {
559 /*
560 * We cannot simply remove the file. The SVID states
561 * that the block remains until the last person
562 * detaches from it, then is deleted. A shmat() on
563 * an RMID segment is legal in older Linux and if
564 * we change it apps break...
565 *
566 * Instead we set a destroyed flag, and then blow
567 * the name away when the usage hits zero.
568 */
569 down(&shm_ids.sem);
570 shp = shm_lock(shmid);
571 err = -EINVAL;
572 if (shp == NULL)
573 goto out_up;
574 err = shm_checkid(shp, shmid);
575 if(err)
576 goto out_unlock_up;
577
578 if (current->euid != shp->shm_perm.uid &&
579 current->euid != shp->shm_perm.cuid &&
580 !capable(CAP_SYS_ADMIN)) {
581 err=-EPERM;
582 goto out_unlock_up;
583 }
584
585 err = security_shm_shmctl(shp, cmd);
586 if (err)
587 goto out_unlock_up;
588
589 if (shp->shm_nattch){
590 shp->shm_flags |= SHM_DEST;
591 /* Do not find it any more */
592 shp->shm_perm.key = IPC_PRIVATE;
593 shm_unlock(shp);
594 } else
595 shm_destroy (shp);
596 up(&shm_ids.sem);
597 goto out;
598 }
599
600 case IPC_SET:
601 {
602 if (copy_shmid_from_user (&setbuf, buf, version)) {
603 err = -EFAULT;
604 goto out;
605 }
606 if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
607 return err;
608 down(&shm_ids.sem);
609 shp = shm_lock(shmid);
610 err=-EINVAL;
611 if(shp==NULL)
612 goto out_up;
613 err = shm_checkid(shp,shmid);
614 if(err)
615 goto out_unlock_up;
616 err=-EPERM;
617 if (current->euid != shp->shm_perm.uid &&
618 current->euid != shp->shm_perm.cuid &&
619 !capable(CAP_SYS_ADMIN)) {
620 goto out_unlock_up;
621 }
622
623 err = security_shm_shmctl(shp, cmd);
624 if (err)
625 goto out_unlock_up;
626
627 shp->shm_perm.uid = setbuf.uid;
628 shp->shm_perm.gid = setbuf.gid;
629 shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
630 | (setbuf.mode & S_IRWXUGO);
631 shp->shm_ctim = get_seconds();
632 break;
633 }
634
635 default:
636 err = -EINVAL;
637 goto out;
638 }
639
640 err = 0;
641out_unlock_up:
642 shm_unlock(shp);
643out_up:
644 up(&shm_ids.sem);
645 goto out;
646out_unlock:
647 shm_unlock(shp);
648out:
649 return err;
650}
651
652/*
653 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
654 *
655 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
656 * "raddr" thing points to kernel space, and there has to be a wrapper around
657 * this.
658 */
659long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
660{
661 struct shmid_kernel *shp;
662 unsigned long addr;
663 unsigned long size;
664 struct file * file;
665 int err;
666 unsigned long flags;
667 unsigned long prot;
668 unsigned long o_flags;
669 int acc_mode;
670 void *user_addr;
671
672 if (shmid < 0) {
673 err = -EINVAL;
674 goto out;
675 } else if ((addr = (ulong)shmaddr)) {
676 if (addr & (SHMLBA-1)) {
677 if (shmflg & SHM_RND)
678 addr &= ~(SHMLBA-1); /* round down */
679 else
680#ifndef __ARCH_FORCE_SHMLBA
681 if (addr & ~PAGE_MASK)
682#endif
683 return -EINVAL;
684 }
685 flags = MAP_SHARED | MAP_FIXED;
686 } else {
687 if ((shmflg & SHM_REMAP))
688 return -EINVAL;
689
690 flags = MAP_SHARED;
691 }
692
693 if (shmflg & SHM_RDONLY) {
694 prot = PROT_READ;
695 o_flags = O_RDONLY;
696 acc_mode = S_IRUGO;
697 } else {
698 prot = PROT_READ | PROT_WRITE;
699 o_flags = O_RDWR;
700 acc_mode = S_IRUGO | S_IWUGO;
701 }
702 if (shmflg & SHM_EXEC) {
703 prot |= PROT_EXEC;
704 acc_mode |= S_IXUGO;
705 }
706
707 /*
708 * We cannot rely on the fs check since SYSV IPC does have an
709 * additional creator id...
710 */
711 shp = shm_lock(shmid);
712 if(shp == NULL) {
713 err = -EINVAL;
714 goto out;
715 }
716 err = shm_checkid(shp,shmid);
717 if (err) {
718 shm_unlock(shp);
719 goto out;
720 }
721 if (ipcperms(&shp->shm_perm, acc_mode)) {
722 shm_unlock(shp);
723 err = -EACCES;
724 goto out;
725 }
726
727 err = security_shm_shmat(shp, shmaddr, shmflg);
728 if (err) {
729 shm_unlock(shp);
730 return err;
731 }
732
733 file = shp->shm_file;
734 size = i_size_read(file->f_dentry->d_inode);
735 shp->shm_nattch++;
736 shm_unlock(shp);
737
738 down_write(&current->mm->mmap_sem);
739 if (addr && !(shmflg & SHM_REMAP)) {
740 user_addr = ERR_PTR(-EINVAL);
741 if (find_vma_intersection(current->mm, addr, addr + size))
742 goto invalid;
743 /*
744 * If shm segment goes below stack, make sure there is some
745 * space left for the stack to grow (at least 4 pages).
746 */
747 if (addr < current->mm->start_stack &&
748 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
749 goto invalid;
750 }
751
752 user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
753
754invalid:
755 up_write(&current->mm->mmap_sem);
756
757 down (&shm_ids.sem);
758 if(!(shp = shm_lock(shmid)))
759 BUG();
760 shp->shm_nattch--;
761 if(shp->shm_nattch == 0 &&
762 shp->shm_flags & SHM_DEST)
763 shm_destroy (shp);
764 else
765 shm_unlock(shp);
766 up (&shm_ids.sem);
767
768 *raddr = (unsigned long) user_addr;
769 err = 0;
770 if (IS_ERR(user_addr))
771 err = PTR_ERR(user_addr);
772out:
773 return err;
774}
775
Stephen Rothwell7d87e142005-05-01 08:59:12 -0700776asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
777{
778 unsigned long ret;
779 long err;
780
781 err = do_shmat(shmid, shmaddr, shmflg, &ret);
782 if (err)
783 return err;
784 force_successful_syscall_return();
785 return (long)ret;
786}
787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788/*
789 * detach and kill segment if marked destroyed.
790 * The work is done in shm_close.
791 */
792asmlinkage long sys_shmdt(char __user *shmaddr)
793{
794 struct mm_struct *mm = current->mm;
795 struct vm_area_struct *vma, *next;
796 unsigned long addr = (unsigned long)shmaddr;
797 loff_t size = 0;
798 int retval = -EINVAL;
799
800 down_write(&mm->mmap_sem);
801
802 /*
803 * This function tries to be smart and unmap shm segments that
804 * were modified by partial mlock or munmap calls:
805 * - It first determines the size of the shm segment that should be
806 * unmapped: It searches for a vma that is backed by shm and that
807 * started at address shmaddr. It records it's size and then unmaps
808 * it.
809 * - Then it unmaps all shm vmas that started at shmaddr and that
810 * are within the initially determined size.
811 * Errors from do_munmap are ignored: the function only fails if
812 * it's called with invalid parameters or if it's called to unmap
813 * a part of a vma. Both calls in this function are for full vmas,
814 * the parameters are directly copied from the vma itself and always
815 * valid - therefore do_munmap cannot fail. (famous last words?)
816 */
817 /*
818 * If it had been mremap()'d, the starting address would not
819 * match the usual checks anyway. So assume all vma's are
820 * above the starting address given.
821 */
822 vma = find_vma(mm, addr);
823
824 while (vma) {
825 next = vma->vm_next;
826
827 /*
828 * Check if the starting address would match, i.e. it's
829 * a fragment created by mprotect() and/or munmap(), or it
830 * otherwise it starts at this address with no hassles.
831 */
832 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
833 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
834
835
836 size = vma->vm_file->f_dentry->d_inode->i_size;
837 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
838 /*
839 * We discovered the size of the shm segment, so
840 * break out of here and fall through to the next
841 * loop that uses the size information to stop
842 * searching for matching vma's.
843 */
844 retval = 0;
845 vma = next;
846 break;
847 }
848 vma = next;
849 }
850
851 /*
852 * We need look no further than the maximum address a fragment
853 * could possibly have landed at. Also cast things to loff_t to
854 * prevent overflows and make comparisions vs. equal-width types.
855 */
856 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
857 next = vma->vm_next;
858
859 /* finding a matching vma now does not alter retval */
860 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
861 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
862
863 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
864 vma = next;
865 }
866
867 up_write(&mm->mmap_sem);
868 return retval;
869}
870
871#ifdef CONFIG_PROC_FS
872static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
873{
874 off_t pos = 0;
875 off_t begin = 0;
876 int i, len = 0;
877
878 down(&shm_ids.sem);
879 len += sprintf(buffer, " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n");
880
881 for(i = 0; i <= shm_ids.max_id; i++) {
882 struct shmid_kernel* shp;
883
884 shp = shm_lock(i);
885 if(shp!=NULL) {
886#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
887#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
888 char *format;
889
890 if (sizeof(size_t) <= sizeof(int))
891 format = SMALL_STRING;
892 else
893 format = BIG_STRING;
894 len += sprintf(buffer + len, format,
895 shp->shm_perm.key,
896 shm_buildid(i, shp->shm_perm.seq),
897 shp->shm_flags,
898 shp->shm_segsz,
899 shp->shm_cprid,
900 shp->shm_lprid,
901 is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
902 shp->shm_perm.uid,
903 shp->shm_perm.gid,
904 shp->shm_perm.cuid,
905 shp->shm_perm.cgid,
906 shp->shm_atim,
907 shp->shm_dtim,
908 shp->shm_ctim);
909 shm_unlock(shp);
910
911 pos += len;
912 if(pos < offset) {
913 len = 0;
914 begin = pos;
915 }
916 if(pos > offset + length)
917 goto done;
918 }
919 }
920 *eof = 1;
921done:
922 up(&shm_ids.sem);
923 *start = buffer + (offset - begin);
924 len -= (offset - begin);
925 if(len > length)
926 len = length;
927 if(len < 0)
928 len = 0;
929 return len;
930}
931#endif